1. Field of the Invention
This invention relates to inflatable devices of the type which are inflated wholly or in part by fluid pressure, for protectively restraining the movement of an occupant relative to a vehicle when the vehicle becomes involved in a collision. More particularly, this invention relates to inflatable confinements of these devices in which differential fluid flow control into and out of the confinement is provided for to eliminate or mitigate in some significant way rebound injury to the occupant under the stated conditions.
2. Description of the Prior Art
Inflatable confinements, i.e., air bags, flexible containers, or cushions for restraining the movement of vehicle occupants during collisions have long been known. In addition, it is also known to provide inflation means such as gas generators and the like to supply primary inflating fluid or gas in which the action of the bag in the process of being inflated is utilized to aspirate ambient air into the bag thereby minimizing the requirement for primary inflating fluid. Furthermore, it is also well known to incorporate additional safety means into the restraint system to prevent rebound injury to the occupant. For example, in U.S. Pat. No. 3,527,475, blowout patches incorporated in an air bag wall give way under the increased pressure experienced by the inflated air bag when impacted by the occupant being restrained during the collision. In U.S. Pat. No. 3,511,519, perforations in a portion of the bag wall permit passage of inflation fluid out of the bag upon occupant impact to deflate the bag and minimize rebound of the occupant therefrom. U.S. Pat. No. 3,758,133 on the other hand, utilizes a valve in the system operative to open when the interior pressure of the bag increases upon occupant impact to permit passage of inflation fluid out of the bag to deflate the bag. Other patents disclosing similar safety devices, also, with some minor variations, representative of the prior art of rebound protection for vehicle occupants during collisions are: U.S. Pat. Nos. 3,762,741, 3,784,225, 3,792,873, 3,799,574, 3,807,754, 3,990,726, 3,991,249 and 4,043,572.
Prior art patents disclosing restraint systems representative of inflatable restraints in which ambient air is aspirated into a confinement to inflate it are the following: U.S. Pat. No. 3,733,091 in which restraint cushions are inflated both by pressure fluid from a primary on-board source of supply and ambient air aspirated through an ambient air receiving chamber defined by movable frontal and base portions of the air bag; U.S. Pat. No. 3,767,225, which utilizes a flutter valve in the bag through which ambient air is aspirated by action of the bag as it is inflated with gas from a primary pressure source; U.S. Pat. No. 3,791,669, which discloses a diffuser-aspirator arrangement to augment inflation rate of an air bag by means of a conical inlet to facilitate entry of the aspirated air thereinto; U.S. Pat. No. 3,938,826, in which pressurized primary gas or fluid from a gas generator is used to aspirate ambient air into the bag, the primary gas and ambient air being mixed therein to inflate the bag; U.S. Pat. No. 4,043,572, previously mentioned, in which pressure fluid from a primary pressure source is used to induce ambient air flow into the bag through uncoverable ports provided; U.S. Pat. No. 4,076,277 in which an inner gas column or tubular air bag is inflated by a gas generating source and air is sucked into an outer bag by action of the inflating columns or tubes; and finally, within the present applicant's personal knowledge is a proposal for an emergency dual chamber crash cushion consisting of an inner, preshaped tube which serves as an inflatable structural frame supporting another outer chamber. However, in none of the aforementioned is it suggested, or in any way even remotely taught to make confinements with flexible, fluid impermeable walls for inflatable restraints to protect vehicle occupants during collisions which incorporate fluid permeable portions in the walls of the confinements having a filamentous surface to permit controlled, differential flow of inflated fluid into and out of the confinement restraining the movement of the occupant relative to the vehicle while eliminating, or mitigating injury from rebound as a result.